## The quantized black hole as a theoretical laboratory

Einstein’s theory of General Relativity gives a description of the gravitational force that has been checked accuratelyfor large systems such as planets and stars.However, it should also be valid at the scale of single atoms and molecules. A serious complication however is that these tiny particles behave in accordance with the laws of quantum mechanics, and while these laws are understood when applied to electricity and magnetism, the gravitational force here seems to be mysterious. To investigate the situation further, theoreticians consider the most extreme configurations of space and time that follow from General Relativity: black holes. We have the Schroedinger equation for the elementary particles. What is the Schroedinger equation for a black hole? Space and time are dynamical entities; do they follow wave equations? We cannot do experiments with real black holes since all known black holes are large and very far away, and so we are forced to do these experiments in our imagination. But we can investigate the internal logic when we attempt at writing universal equations, but these give rise to fierce discussions.-->